I wonder if all gems change their clothes over time, or just the ones that lived on Earth. After all, the Crystal Gems were trying to emulate the human experience as best they could. Homeworld gems have no need for such frivolity. But still, they could have changes in fashion, right? Or maybe gem culture on Homeworld never changes. After all, the Diamonds have been ruling for over 5,000 years. So maybe things don't really change there. Maybe that's why Lapis was surprised that Earth was changing all the time, and never stayed the same.